Rotatable electrical connector



H. E. PHILLIPS 3,321,729

ROTATABLE ELECTRICAL CONNECTOR 2 Sheets-Sheet 1 May 23, 1967 Filed Oct. 22, 1964 I INVENTOR.

hermanA-TffiJ/f 3, I 20 44 1 B 0 40 46 I5 M /MM Attorneys.

H. E. PHlLLlFS ROTATABLE ELECTR I CAL CONNECTOR May 23, 1967 2 Sheets-Sheet 6 Filed Oct. 22, 1964 b 0 5 M, 3 "2 JZ/ 0 5 p 4 k/ W/ a 0 n 5 0/: 3 o M 0 9 6/ I x p y I A 2 $243? y 07 I 1 a w L 0 d 0 a 6 0 m 3 M U United States Patent Ofiice 3,321,729 Patented May 23, 1967 3,321,729 ROTATABLE ELECTRECAL CONNECTOR Hermon E. Phillips, RED. Lake James, Angola, Ind. 46703 Filed Oct. 22, 1964, Ser. No. 495,705 12 Claims. (Cl. 339-8) This invention relates generally to electrical wiring devices, and more particularly to an improved rotatable electrical connector.

There are many instances Where a portable electrical appliance, such as a hand tool or iron, which has its cord plugged into a convenience outlet, is manipulated in such a manner that the cord becomes twisted. It is therefore desirable to provide a rotatable electrical connector by which conventional male electrical plug may be connected to a convenience outlet thereby to permitmanipulation of the appliance without twisting of the cord. It is further desirable to provide a convenience outlet incorporating a rotatable electrical connector to which a conventional male plug may be connected directly. In order to have such rotatable electrical connectors commercially suitable for household use, they must be characterized by simplicity, ease of assembly, and low cost. A rotatable electrical connector is described and illustrated in my Patent No. 2,123,421. That connector employed two metallic bearings of the anti-friction type for providing the rotatable electrical connection, the two bearings being the most expensive components of the device. It is therefore desirable to provide an improved rotatable connector in which one of the bearings is eliminated, and which, moreover may be more readily fabricated and assembled in production.

It is therefore an object of my present invention to provide an improved rotatable electrical connector.

My present invention, in its broader aspects, provides a rotatable electrical connector comprising a first member formed of molded insulating material and having a surface with a portion extending axially therefrom, the extension portion having .a cylindrical surface and an end surface. Annular bearing means is provided having relatively rotatable inner and outer parts, the inner bearing means part being seated on the cylindrical surface with a light press-fit. The first member has a first electrical lead molded therein with one end thereof exposed to the cylindrical surface and contacting the inner bearing means part. The first member also has a second electrical lead molded therein with a first end thereof exposed to the end surface, the first member further having means molded therein for making electrical contact with the other ends of the first and second leads, respectively. A second member is provided formed of molded insulating material and having a cavity formed therein defining a cylindrical wall and a bottom wall. The first member extension portion of the bearing means is positioned in the cavity with the outer bearing means part engaging the cylindrical wall with a press-fit so that the first and second members are relatively rotatable. The second member has a third electrical lead molded therein with one end thereof exposed to the cylindrical wall and contacting the outer bearing means part. The second member also has a fourth electrical lead molded therein with a first end exposed to the bottom wall of the cavity. The second member further has means molded therein for making electrical contact with the other ends of the third and fourth leads, respectively, and rotatable contact means are provided connecting the first ends of the second and fourth leads.

The above-mentioned and other features and objects of this invention and the manner of attaining them will become more apparent and the invention itself will be best understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a cross-sectional view showing one embodiment of the invention, taken along line 11 of FIGURE 1A;

FIG. 1A is a top view of the embodiment of FIG. 1;

FIG. 2 is a cross-sectional view showing a modification of the embodiment of FIG. 1;

FIG. 3 is a cross-sectional view showing another embodiment of the invention; and

HG. 4 is a cross-sectional view showing a convenience outlet incorporating the rotatable electrical connector of the invention.

Referring now to FIG. 1, the rotatable electrical connector, generally indicated at 10, comprises a first member 12 formed of suitable molded insulating material. Member 12 has a first cylindrical portion 14 having top and bottom fiat radial surfaces 16, 18, and a second cylindrical portion 20 coaxial with portion 14 and extending axially from end surface 16. Portion 20' has a diameter substantially smaller than the diameter of portion 14 and has a radial end surface 22. A small annular shoulder 24 joins the top surface 16 of cylindrical portion 14 and the cylindrical outer surface 25 of cylindrical portion 20.

An axially elongated annular sleeve bearing 28 is provided having inner and outer bearing parts 30, 32, the inner bearing part 30 being seated on the cylindrical surface 26 of the cylindrical portion 20 of member 12 with a light press-fit. For a purpose to be hereinafter more fully described, the bearing surface 34 defined by the inner and outer bearing parts 30, 32 tapers outwardly away from cylindrical surface 26 and upwardly from end surface 16, as shown.

A first electrical contact 36 is molded in the cylindrical portion 20 of the member 12 and is exposed to the cylindrical surface 26 so as electrically to contact inner bearing part 30. The inner and outer bearing parts 30, 32 are formed of suitable electrically conductive material. A pair of male prongs 38, 41 of a conventional electrical plug are provided molded in cylindrical portion 14 of member 12 and extend axially from bottom end surface 18, as shown. A first electrical lead 42 is molded in member 12 and is suitably connected to contact 36 and prong 40, as shown.

A coaxial recess 44 is formed in the end surface 22 of the cylindrical portion 20 of member 12 and a suitable electrical contact 46 is molded in cylindrical portion 20 and communicates with recess 44, as shown. Another electrical lead 48 is molded in member 12 and is suitably connected to contact 46 and prong 38, as shown.

' Another cylindrical member 50 is provided formed of suitable molded insulating material and having a flat radial top surface 52 and a radial bottom surface 54. Member 50 preferably has approximately the same diameter as cylindrical portion 14 ofmember 12. Member I 15 has a coaxial cylindrical cavity 56 formed therein from the bottom end surface 54, the cavity 56 being defined by a cylindrical side wall 58 and a radial bottom wall 60. A small annular shoulder 62 joins cylindrical side wall 58 and radial end wall 60. The outer bearing part 32 engages the cylindrical side wall 58 of cavity 56 with a light press-fit, the bottom and top ends of bearing 28 respectively engaging shoulders 24, 62 when the connector is assembled, as shown. i

It will now be seen that by virtue of the outwardly and upwardly tapered configuration of the bearing surface 34 of bearing 28 and by virtue of the light press-fit of cylindrical portion 20 of member 12 in the inner bearing part 30 and the light press-fit on the cylindrical side wall 58 of cavity 56 of member 50 over the outer bearing part 32, the connector is held in assembled relation once it is assembled and separation of member 12 with respect to member 50 is thereafter inhibited.

A pair of elongated openings 64, 66 are formed in member- 50 extending axially from end 52 toward end 54, openings 64, 66 being proportioned and arranged to receive the prongs of another conventional male electrical plug, similar to prongs 38, 40. Contact element 68 is provided having a portion 70 molded in member 50 and an elongated prong-engaging spring portion 72 positioned in opening 64. Bottom wall 60 of cavity 56 has a shallow recess 74 formed therein coaxial with recess 44 and a contact element 76 is provided molded in member 50 and exposed to recess 74. Electrical lead 78 is molded in member 50 and connects portion 70 of contact element 68 and contact 76. A suitable spring Washer 80 is positioned in recess 44 and has its opposite ends resiliently engaging contact 46 and contact 76, as shown, thereby electrically connecting prong 38, lead 48, and contact 46 to contact 76, lead 78 and contact element 68.

Another contact element 82 is provided, having a portion 84 molded in and extending through wall portion 86 of member 50 which separates opening 66 from cavity 56 so that portion 84 engages the outer bearing part 32. Contact element 82 has another elongated prong-engagin g springportion 88 positioned in opening 66. It will thus be seen that prong 40 is electrically connected to contact element 82 by lead 42, contact 36, the inner and outer bearing parts 30, 32 and contact portion 84.

It will now be seen that members 12 and 50 are molded with their respective prongs, leads, and contacts therein, and that in order to assemble the connector, it is merely necessary to assemble the bearing 28 consisting of the preassembled parts 30, 32 over portion 20 of member 12 with the aforesaid light press-fit, position spring 58 in recess 44, and assemble member 50 over bearing 28 with a light press-fit.

Referring now to FIG. 2 in which like elements are indicated by like reference numerals, an embodiment of the rotatable electrical connector of the invention is shown in which a conventional ball bearing 90 having inner and outer races 92, 94 is substituted for the tapered sleeve bearing 28 of FIG. 1. It will be seen in the embodiment of FIG. 1 that because of the elongated configuration of the bearing 28, the elongated prong-receiving opening 64, 66 extended axially along the cylindrical wall 58 of cavity 56, being spaced therefrom by wall portion 86, whereas, with the employment of the axially shorter but radially larger anti-friction bearing 90, openings 64', 66' extend toward bottom wall 60' of cavity 56 terminating short of wall 60 to define wall portion 96. Resultantly, portion 20 of member 12' is axially shorter and cavity 56' is axially shallower than in the embodiment of FIG. 1.

The inner ball race 92 of bearing 90 is again assembled over portion 20' of the pre-assembled member 12' with a light press-fit and cylindrical surface 58' of cavity 56 is assembled over the outer race 94 with a light PICSS-tfit. It will be seen that this press assembly of the members 12', 50' on bearing 94, together with the inherent characteristics of the ball bearing 90 again inhibits axial separation of members 12', 50 once the connector has been assembled.

In this embodiment, contact 98 is molded in member 50' and exposed to cylindrical wall 58 of cavity 56 so as to engage outer race 94 of bearing 90, contact 98 being connected to portion 84' of contact element 82 by electrical lead 100 molded in member 50'.

Referring now to FIG. 3 in which like elements are still indicated by like reference numerals, another embodiment is shown in which the first cylindrical member 12" has a coaxial cylindrical recess 101 formed therein definedby cylindrical side walls 102, 104 joined by a radial step 106 and a flat radial bottom wall 108 joined to cylindrical side wall 104 by a shoulder 110. Member 50 has a cylindrical portion 112 with top and bottom radial surfaces 114, 116 and, a coaxial cylindrical portion 118 extending axially from radial surface 116 and having a radial end surface 120. Member 50" is coaxially positioned within cavity in member 12" with its outer cylindrical wall 122 defining a small clearance with the cylindrical wall 102 of cavity 101 and with its radial end Wall having a small clearance from bottom wall 108 of cavity 101. A shoulder 124 joins cylindrical extension portion 118 to the bottom radial surface 116 of member 50".

The innerbearing race 92 of ball bearing 90 is assembled over the cylindrical extension portion 118 of member 50" with a light press-fit with one end thereof engaging shoulder 124, and the outer bearing race 94 is assembled within cylindrical wall 104 of cavity 101 with a light pressfit and with its other end engaging shoulder 110, thereby rotatably mounting member 50" within member 12", as shown. It will be seen that the top radial surface 114 of member 50 is generally flush with the top end 126 of member 12".

In this embodiment, a shallow coaxial recess 128 is formed in bottom wall 108 of cavity 101 and a deeper recess 130 coaxial with recess 128 is formed in portion 118 of member 50". Contact 46" is molded in member 12" and is exposed to recess 128, and is connected to male prong 38 by electrical lead 48" also molded in member 12". Contact 36" is molded in member 12" and is exposed to cylindrical wall 104 of cavity 101 so as to contact outer race 94 of bearing 90, contract 36" being congectiig to prong 40 by electrical lead 42" molded in mem- Prong-receiving openings 64", 66" are formed in member 50" extending toward but terminating axially short of bottom radial surface 116. Contact 76" is molded in member 50 and is exposed to recess 138, contact 76 being connected to portion 70" of contact element 68" by electrical lead 78" molded in member 50. Contact 98 is also molded in member 50" and is exposed to the cylindrical surface of portion 118 so as to engage the outer bearing race 94 of bearing 90, contact 98 being connected to portion 84" of contact element 82" by electrical lead 100" also molded in member 50". Spring washer 80 is again provided located in recess 130 of member 50 and having its ends resiliently engaging contacts 46, 76.

It will be seen that the embodiment of FIG. 3, in common with the embodiments of FIGS. 1 and 2. merely requires assembly of the spring washer 80 in recess 130 and bearing 90 on extension portion 118 of member 50" with a light press-fit, and final assembly of member 12 over bearing 90 with a light press-fit, axial separation of members, 12", 50" thereafter being inhibited.

Referring now to FIG. 4 in which like elements are still indicated by like reference numerals, an arrangement is shown in which the embodiment of FIG. 3 is incorporated in a duplex convenience outlet. Here, member 12 is generally rectangular rather than cylindrical as in the previous embodiments, and has tWo cavities 101 formed therein each rotatably accommodating a member 50" as in the embodiment of FIG. 3.

In this embodiment, the male prongs 38, 40 are eliminated and contact elements 128, 130 are molded in member 12" and exposed to its bottom surface 18". Contact elements 128, 130 are respectively connected to electrical leads 42", 48" and respectively threadingly receive conventional screws 132, 134 by which electrical connections may be made, as is well known to those skilled in the art.

Conventional mounting brackets 136 are molded in member 12" and are employed in conventional fashion for mounting the duplex convenience outlet in a conventional outlet box. The upper end 126 of member 121" is proportioned and arranged to receive a conventional cover plate 138 which is secured to member 12 by means of a suitable threaded fastener 140.

It will be readily seen that either of the embodiments of. F-IGS.. 1 or 2 may equally advantageously be incorpor- 5 ated in a convenience outlet in the manner shown in FIG. 4.

The term light press-fit as used herein refers to a snug, friction fit obtained by pressing with relatively light force, i.e., a force which is insufficient either to distort the bearing or to fracture the molded plastic material. It will be understood that the spring portions 72, 88 of the contact elements 68, 82 of the several embodiments of the invention are preferably formed of relatively thin, sheet material, such as brass, with their distal ends engaging the side walls of openings 64, 66, thus practically preventing abutting engagement with an entering male prong.

While there have been described above the principles of this invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of the invention.

What is claimed is:

1. A rotatable electrical connector comprising: a first member formed of molded insulating material and having a surface with a portion extending axially therefrom, said extension portion having a cylindrical surface and an end surface; annular bearing means having relatively rotatable inner and outer parts, said inner bearing means part being seated on said cylindrical surface with a friction-fit; said first member having a first electrical lead molded therein with one end thereof exposed to said cylindrical surface and contacting said inner bear-ing means part; said first member having a second electrical lead molded therein with a first end thereof exposed to said end surface; said first member having first means molded therein for making electrical contact with the other ends of said first and second leads, respectively; a second member formed of molded insulating material and having a cavity formed therein defining a cylindrical wall and a bottom wall; said first member extension portion and said bearing means being positioned in said cavity with said outer bearing means part engaging said cylindrical wall with a frictionfit whereby said first and second members are relatively rotatable and axial separation of said members is inhibited; said second member having a third electrical lead molded therein with one end thereof exposed to said cylindrical wall and contacting said outer bearing means part; said second member having a fourth electrical lead molded therein with a first end thereof exposed to said bottom wall; said second member having second means molded therein for making electrical contact with the other ends of said third and fourth leads, respectively; and rotatable contact means connecting said first ends of said second and fourth leads.

2. The connector of claim 1 wherein said bearing means is an anti-friction bearing having inner and outer bearing races, said inner race being said inner part and said outer race being said outer part.

3. The connector of claim 1 wherein said bearing means is a sleeve bearing.

4. The connector of claim 1 wherein said bearing means is a sleeve bearing, said inner and outer parts defining a tapered bearing surface, said tapered bearing surface extending outwardly away from said cylindrical surface in a direction toward said bottom wall thereby further inhibiting axial separation of said first and second members.

5. The connector of claim 1 wherein one of said end surface and said end wall have a recess formed therein coaxial with said cylindrical surface and wall, said first end of the respective second and fourth leads being exposed in said recess, and wherein said rotatable contact means comprises a resilient contact element having 0pposite ends respectively engaging said first ends of said second and fourth leads and extending into said recess being located thereby.

6. The connector of claim 1 wherein the contact means of one of said members comprises the male prongs of an electrical plug.

7. The connector of claim 1 wherein one of said members has a pair of openings formed therein for receiving the male prongs of an electrical plug, and wherein the contact means of said one member are respectively disposed in said openings and adapted to engage said prongs.

8. A rotatable electrical connector comprising: a first member formed of molded insulating material, said first member having a first cylindrical portion with first and second radial end surfaces and a second cylindrical portion coaxial with said first portion and extending axially from said first surface, said second portion having a third radial end surface and a smaller diameter than said first portion, said first member having a solid cross-section; an annular bearing having relatively rotatable inner and outer parts, said inner bearing part being seated on said second portion of said first member with a friction-fit, said bearing having a first end parallel with and closely spaced from said first surface; said first member having a pair of male prongs of an electrical plug molded therein and extending axially from said second surface; said first member having a first electrical contact molded in said second portion and engaging said inner bearing part; said first member having a first electrical lead molded therein and connecting said first contact and one of said prongs; said third surface having a first recess formed therein coaxial with said first and second portions; said second portion having a second electrical contact molded therein and exposed to said first recess; said first member having a second electrical lead molded therein and connecting said second contact and the other of said prongs; a second cylindrical member formed of molded insulating material and having fourth and fifth radial end surfaces, said second member having a diameter generally the same as that of said first portion, said second member having a coaxial cylindrical cavity formed in said fourth surface defined by a cylindrical wall and a radial bottom Wall; said second portion and said bearing being seated in said cylindrical cavity with said outer bearing part engaging said cylindrical wall with a friction-fit whereby said first and second members are relatively rotatable and axial separation of said members is inhibited, said second and fourth end surfaces being closely spaced, said bearing having a second end parallel with and closely spaced from said bottom wall, said third end surface and said bottom wall being closely spaced; said bottom wall having a second recess formed therein coaxial with said second member; said second member having a pair of axial openings formed therein from said fifth end surface and adapted to receive the male prongs of another electrical plug; said second member having third and fourth electrical contacts molded therein respectively exposed to said openings and adapted to engage said other prongs; said second member having a fifth electrical contact molded therein and engaging said outer bearing part; said second member having a third electrical lead molded therein and connecting said fifth contact and said third contact; said second member having a sixth electrical contact molded therein and exposed to said second recess; said second member having a fourth electrical lead molded therein and connecting said sixth contact and said fourth contact; and a resilient contact element having opposite ends respectively rotatably engaging said second and fifth contacts and extending into at least one of said recesses being located thereby.

9. The connector of claim 8 wherein said second member has a first portion extending axially from said fourth end surface and having said cylindrical recess formed therein, and a second portion extending axially from said bottom wall to said fifth end surface, and wherein said openings are disposed entirely in said second portion of said second member, said openings being spaced apart by a distance less than the diameter of said cylindrical opening.

10. The connector of claim 8 wherein said openings are spaced apart by a distance greater than the diameter of said cylindrical recess, said openings respectively extending axially along the sides of said cylindrical cavity and being separated therefrom by axial walls, and wherein said fifth and third contacts and said third lead are integrally formed and extend through one of said axial walls.

11. The connector of claim 8 wherein said bearing includes means further inhibiting axial separation of said inner and outer parts.

12. A rotatable electrical connector comprising: a first member formed of molded insulating material and having first and second axially spaced, parallel end surfaces, said first member having a cylindrical cavity formed therein from said first end surface defined by a cylindrical wall' and a radial bottom wall; an annular bearing having inner and outer parts, said outer bearing part being seated in said cylindrical Wall with a friction-fit, said bearing having one end parallel with and closely spaced from said bottom wall; said first member having a first electrical contact molded therein and engaging said outer bearing part; said first member having second and third electrical contacts molded therein and exposed on said second end surface; said first member having a first electrical lead molded therein and connecting said first and second contacts; said first member having a first recess formed in said bottom wall coaxial with said cylindrical wall; said first member having a fourth electrical contact molded therein and exposed to said first recess; said first member having a second electrical lead molded therein and connecting said third and fourth contacts; a second member formed of molded insulating material, said second member having a first cylindrical portion with third and fourth radial end surfaces and a second cylindrical portion coaxial with said first portion and extending axially from said fourth surface, said second portion having a fifth radial end surface and a diameter smaller than that of said first portion; said second member being positioned in said cavity with said first portion closely spaced from said cylindrical wall and with said first and third end surfaces generally flush and with said fifth end surface and said bottom wall closely spaced, said inner bearing part being seated on said second portion with a friction-fit whereby said first and second members are relatively rotatable and axial separation of said members is inhibited; said bearing having a second end parallel with and closely spaced from said fourth wall; said second member having a pair of axial openings formed therein from said third end surface and adapted to receive the male prongs of an electrical plug; said second member having fifth and sixth electrical contacts molded therein and respectively exposed to said openings and adapted to engage said prongs; said second member having a seventh electrical contact molded therein engaging said inner bearing part; said second member having a third electrical lead molded therein connecting said fifth and seventh contacts; said second member having a second recess formed in said fifth end surface coaxial with said second portion; said second member having an eighth electrical contact molded therein exposed to said second recess; said second member having a fourth electrical lead molded therein connecting said sixth and eighth contacts; and a resilient contact element having opposite ends respectively rotatably engaging said fourth and eighth contacts and extending into at least one of said recesses being located thereby.

References Cited by the Examiner UNITED STATES PATENTS 1,222,585 4/1917 Carlson 339183 1,280,867 10/1918 Scheel 339-8 1,837,890 12/1931 Baker 339-8 2,119,168 5/1938 Kus 339-2 2,248,759 7/ 1941 Hollander 339 8 2,654,869 10/1953 Mudd 339-8 FOREIGN PATENTS 272,686 3 1951 Switzerland.

MARVIN A. CHAMPION, Primary Examiner. ALFRED S. TRASK, Examiner. 

1. A ROTATABLE ELECTRICAL CONNECTOR COMPRISING: A FIRST MEMBER FORMED OF MOLDED INSULATING MATERIAL AND HAVING A SURFACE WITH A PORTION EXTENDING AXIALLY THEREFROM, SAID EXTENSION PORTION HAVING A CYLINDRICAL SURFACE AND AN END SURFACE; ANNULAR BEARING MEANS HAVING RELATIVELY ROTATABLE INNER AND OUTER PARTS, SAID INNER BEARING MEANS PART BEING SEATED ON SAID CYLINDRICAL SURFACE WITH A FRICTION-FIT; SAID FIRST MEMBER HAVING A FIRST ELECTRICAL LEAD MOLDED THEREIN WITH ONE END THEREOF EXPOSED TO SAID CYLINDRICAL SURFACE AND CONTACTING SAID INNER BEARING MEANS PART; SAID FIRST MEMBER HAVING A SECOND ELECTRICAL LEAD MOLDED THEREIN WITH A FIRST END THEREOF EXPOSED TO SAID END SURFACE; SAID FIRST MEMBER HAVING FIRST MEANS MOLDED THEREIN FOR MAKING ELECTRICAL CONTACT WITH THE OTHER ENDS OF SAID FIRST AND SECOND LEADS, RESPECTIVELY; A SECOND MEMBER FORMED OF MOLDED INSULATING MATERIAL AND HAVING A CAVITY FORMED THEREIN DEFINING A CYLINDRICAL WALL AND A BOTTOM WALL; SAID FIRST MEMBER EXTENSION PORTION AND SAID BEARING MEANS BEING POSITIONED IN SAID CAVITY WITH SAID OUTER BEARING MEANS PART ENGAGING SAID CYLINDRICAL WALL WITH A FRICTIONFIT WHEREBY SAID FIRST AND SECOND MEMBERS ARE RELATIVELY ROTATABLE AND AXIAL SEPARATION OF SAID MEMBERS IS INHIBITED; SAID SECOND MEMBER HAVING A THIRD ELECTRICAL LEAD MOLDED THEREIN WITH ONE END THEREOF EXPOSED TO SAID CYLINDRICAL WALL AND CONTACTING SAID OUTER BEARING MEANS PART; SAID SECOND MEMBER HAVING A FOURTH ELECTRICAL LEAD MOLDED THEREIN WITH A FIRST END THEREOF EXPOSED TO SAID BOTTOM WALL; SAID SECOND MEMBER HAVING SECOND MEANS MOLDED THEREIN FOR MAKING ELECTRICAL CONTACT WITH THE OTHER ENDS OF SAID THIRD AND FOURTH LEADS, RESPECTIVELY; AND ROTATABLE CONTACT MEANS CONNECTING SAID FIRST ENDS OF SAID SECOND AND FOURTH LEADS. 